1. Field of invention
The present invention relates to a wireless local area network (WLAN). More particularly, the present invention relates to a method for increasing link capacity in the wireless local area network (WLAN).
2. Description of the Invention
The wireless local area network (WLAN) is a fast-growing market designed to provide the flexibility of wireless access into the office, home, production, or public environment. This unprecedented growth is fueled by the popularity of portable end-user devices and advances in wireless data communications.
Basically, there are two variants of WLAN, infrastructure-based and ad hoc. FIG. 1 illustrates a typical infrastructure network that is capable of providing access to other networks. In this infrastructure-based wireless network, communication typically takes place only between the wireless nodes and the access point (AP), not directly between the wireless nodes. FIG. 2(a) and FIG. 2(b) illustrate ad hoc wireless networks with different end-user devices. In the ad hoc network, each node can communicate with another node if they are within each other's radio range or if other nodes can forward the message.
In an infrastructure network, the wireless nodes, called stations (STA), can exchange data via the AP. The stations and the AP, which are within the same radio coverage, are known as a basic service set (BSS). The main functions of the AP is to support roaming (i.e., changing access points), synchronize within a BSS, support power management, and control the medium access to support time-bounded service within a BSS. Several BSSs (or APs) are interconnected via a system, called the distribution system, to form a single network to extend the wireless coverage area.
In contrast to the wireline technologies, the WLAN is typically restricted in its diameter to buildings, a campus, a single room, etc., and has much lower bandwidth due to limitations in radio transmission (e.g., typically 1–11 Mbit/s). Thus, it is highly desirable to utilize the wireless link bandwidth efficiently in the WLAN.